Comparison

TASSTA T.Flex vs SimpleX Chat

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

TASSTA T.Flex

This app provides mission-critical communication for professionals in demanding situations. It offers voice and video calls, secure messaging, location tracking, and task management, ensuring reliable connectivity for public safety and business operations.

Highlights
  • Voice and video calls
  • Secure messaging
  • Location tracking
  • Task management
  • Lone worker protection
  • Emergency alerts
Features
Read full description

T.Flex is an all-in-one mission critical communications powerhouse that connects people in a variety of ways in a wide range of situations. Its capabilities comprise voice and video calls, messaging, tracking (including indoor localization), task management and more. The uses of the app are versatile. For some users, it helps ensure smooth operation of their business. For others, it's part of the security toolset. Importantly, it can be vital in responding to dangerous incidents where lives depend on timely communication. Whether you're a logistics specialist, a guard on patrol, a firefighter or a police officer, you will appreciate the reliable power of T.Flex, its focus and ease of use. This app is the client-side component of the TASSTA framework. TASSTA provides mission critical push-to-talk (MC-PTT) capabilities in LTE networks over the Internet Protocol (IP) and builds a comprehensive communications and emergency response solution on that foundation. The following are some highlights of the TASSTA features that T.Flex implements. Voice communication features Call capabilities are at the heart of mission-critical communications. In addition to the obligatory group and individual calls, T.Flex offers an extended set of voice and video call types. • Individual, group and channel calls • Emergency calls • Priority calls • Video calls • Offline user calls • Voice recording and playback Messaging features In situations where voice communication is not your first choice of format, use free-form or template-based text messages, or send arbitrary files over your TASSTA network. • Text and file exchange • Template-based status messages Lone worker protection features Intended for ensuring the safety of employees who are working in hazardous conditions, these features rely on sensor and battery charge data. These readings can indicate emergencies and cause alerts to be triggered. • Sensor state tracking • Automated alerts (such as Man Down) based on sensor data analysis • Battery charge monitoring Location and tracking features Always-on location tracking is a core component of T.Flex operation and in many cases the reason to use the app. Access to location is required by dispatchers for ensuring personnel safety and tracking assets. • Subscriber identification and location markers • Detailed street view • Guard tour planning • Waypoints • Indoor localization Other features • Remote listening and camera • Task management and control Note that the feature set for your particular T.Flex setup will be as broad or as lean as your TASSTA administrators configure it to be.

About

SimpleX Chat

This secure messaging app offers unparalleled privacy by eliminating user identifiers. Enjoy end-to-end encrypted messages, calls, and files with features like disappearing messages and incognito mode. Connect via invitation links without needing phone numbers or emails.

Highlights
  • No user identifiers
  • End-to-end encrypted messages
  • Disappearing messages
  • Incognito mode
  • Encrypted file and voice messages
  • Secret chat groups
  • Encrypted portable chat database
Features
Read full description

SimpleX - the first messaging network without user identifiers of any kind (not even random numbers) - 100% private by design! Security assessments by Trail of Bits: 2022: https://simplex.chat/blog/20221108-simplex-chat-v4.2-security-audit-new-website.html 2024: https://simplex.chat/blog/20241014-simplex-network-v6-1-security-review-better-calls-user-experience.html SimpleX Chat features: - quantum resistant end-to-end encrypted messages, with editing, replies and deletion. - disappearing messages with opt-out per contact/group. - message reactions. - delivery receipts, with opt-out per contact or group. - multiple chat profiles, with hidden profiles. - app access and self-destruct passcodes. - incognito mode - unique to SimpleX Chat. - end-to-end encrypted images and files. - voice messages up to 5 minutes – also end-to-end encrypted. - "live" messages – they update for all recipients as you type them, every few seconds - unique to SimpleX Chat. - connect via one-time invitation links or via long-term public addresses. - secret chat groups - only group members know the group exists and who is the member. - end-to-end encrypted audio and video calls. - connection security code verification, for contacts and group members – to protect from man-in-the-middle attacks (e.g. invitation link substitution). - end-to-end encrypted push notifications (they contain only encrypted meta-data, not the actual content). - encrypted portable chat database - you can transfer your chat contacts and history to another device. - all local files and media are encrypted by default. - animated images and "stickers" (e.g., from GIF and PNG files and from 3rd party keyboards). SimpleX Chat advantages: - privacy of your identity, profile, contacts and metadata: unlike any other existing messaging platform, SimpleX uses no phone numbers or any other identifiers assigned to the users - not even random numbers. This protects the privacy of who you are communicating with, hiding it from SimpleX platform servers and from any observers. - complete protection against spam and abuse: as you have no identifier on SimpleX platform, you cannot be contacted unless you share a one-time invitation link or an optional temporary user address. - full ownership, control and security of your data: SimpleX stores all user data on client devices, the messages are only held temporarily on SimpleX relay servers until they are received. - decentralized proxied peer-to-peer network: you can use SimpleX Chat via your own relay servers and still communicate with people using pre-configured or any other SimpleX relay servers. - fully open-source code. You can connect to anybody you know via link or scan QR code (in the video call or in person) and start sending messages instantly - no emails, phone numbers or passwords needed. Your profile and contacts are only stored in the app on your device - relay servers do not have access to this information. All messages are end-to-end encrypted using open-source quantum resistant double-ratchet protocol; the messages are delivered via relay servers using open-source SimpleX Messaging Protocol. Please send us any questions via the app (connect to the team via the app settings!), email chat@simplex.chat or submit issues on GitHub (https://github.com/simplex-chat/simplex-chat/issues) Ream more about SimpleX Chat at https://simplex.chat Get source code in our GitHub repo: https://github.com/simplex-chat/simplex-chat Follow us on X/Twitter (@SimpleXChat), Reddit (r/SimpleXChat/) and Mastodon (https://mastodon.social/@simplex) for the latest updates.

Screenshots

TASSTA T.Flex4 screens
SimpleX Chat4 screens

Verdict

The call

The clearest difference is rating: TASSTA T.Flex at 5.0 against SimpleX Chat's 4.3. TASSTA T.Flex also leads on device support (4 vs 2). SimpleX Chat's advantage is ratings volume (276 vs 1) and update cadence (every 2 weeks vs every 6 weeks). On price, ads, in-app purchases and monetization model there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

TASSTA T.Flex holds the better App Store score, 5.0 against 4.3. That said, the two scores are not equally well evidenced: SimpleX Chat has 276 ratings behind it against 1, so its average is the more settled of the two.

UpkeepUpdate frequency

TASSTA T.Flex ships an update every 6 weeks, SimpleX Chat every 2 weeks. The most recent releases landed on October 20, 2026 and October 30, 2026 respectively.

Scorecard4 real differences · 6 level
TASSTA T.Flex versus SimpleX Chat: the parameters behind the verdict, then further details
ParameterTASSTA T.FlexSimpleX Chat
PriceFreeFree
Rating5.0 (1 ratings) — better4.3 (276 ratings)
Positive reviews—56.2% of reviews
Number of ratings1276 — better
Update frequencyEvery 6 weeksEvery 2 weeks — better
AdsNoNo
In-app purchasesNoNo
MonetizationFreeFree
DevicesiPhone, iPad, iPod, Apple Watch — betteriPhone, iPod
Requires iOS14.0 — better15.0
Further details — not scored
Size64 MB193 MB
Age rating4+12+
DeveloperTASSTA GmbHSimpleX Chat

Customer experience

TASSTA T.Flex

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

SimpleX Chat

All ratings268 ratings
Positive79.1%
Neutral6.0%
Negative14.9%
Written reviews210 reviews
Positive56.2%
Neutral14.8%
Negative29.0%

Bugs and requests

TASSTA T.Flex

Not enough reviews yet to summarise bugs or requests.

SimpleX Chat

Reported bugs

19 issues
  • App crashes on startup (v6.2 update)
  • Keyboard unresponsive on iOS 26
  • Messages not appearing until app is opened
  • Notifications not working despite correct settings
  • Chat freezing and lag on iPhone
Show 14 more
  • QR code scanning not working on iPad
  • Desktop-phone sync connection failures
  • Auto-delete messages interrupting voice recordings
  • Typing inserts extra characters
  • iOS 17 keyboard autofill interferes with typing
  • Chat object unresponsive but moveable (delete)
  • Backup restoration key confirmation fails if contact offline
  • Server switching not reflected in chats
  • Cannot change sending server for stuck messages
  • Connection errors when creating chat links
  • Video upload takes hours
  • Call notifications appearing in Russian
  • Random photo auto-attachment during typing
  • Unable to unsend or delete sent attachments

Requested features

14 requests
  • Read receipts option
  • Typing indicators
  • Bot maker feature like Telegram
  • Multiple image attachment with descriptions
  • Better emoji reaction selection
Show 9 more
  • Mac desktop app
  • Web app (PWA)
  • iPad optimization
  • Improved group discovery/search
  • Global self-destruct message settings
  • Pin photos in group welcome messages
  • Chinese input method support
  • Ringing tone during calls
  • Speakerphone launch option before call pickup

In-app purchases

None

TASSTA T.Flex

No in-app purchases

None

SimpleX Chat

No in-app purchases

Questions

Is TASSTA T.Flex free?
TASSTA T.Flex is free to download, with no in-app purchases.
Is SimpleX Chat free?
SimpleX Chat is free to download, with no in-app purchases.
Which has better reviews, TASSTA T.Flex or SimpleX Chat?
TASSTA T.Flex is rated higher. TASSTA T.Flex averages 5.0 out of 5 from 1 ratings, while SimpleX Chat averages 4.3 from 276 ratings.
Do TASSTA T.Flex or SimpleX Chat have ads?
Neither TASSTA T.Flex nor SimpleX Chat shows ads.
Which is updated more often, TASSTA T.Flex or SimpleX Chat?
TASSTA T.Flex ships an update every 6 weeks, and SimpleX Chat every 2 weeks. Most recently, TASSTA T.Flex was updated on October 20, 2026 and SimpleX Chat on October 30, 2026.

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